The conventional bicycle gear shift indicating device is generally provided with a plurality of numerals which are intended to designate the gear shift levels and are printed or engraved on the rotary shell of the device. The marks of the shift numerals are susceptible to being gradually erased by the rubbing friction between the rotary shell and the hand of a bicyclist.
The U.S. Pat. No. 4,270,481 discloses a lever operating device for the bicycle gear-shifting system. The device is not entirely effective in design in that the size of the gear shift indicating member is dependent on the rotating size, and that the indicating member can not be therefore seen with ease by the bicyclist. Such a structural deficiency as described above is overcome by an invention which is disclosed in the U.S. Pat. No. 5,601,001. However, the latter invention is limited in design in that the size of the bicycle speed indicator is relatively large, and that the bicycle speed indicator is complexed in construction, and further that the bicycle speed indicator is prone to cause a visual error.
The U.S. Pat. Nos. 5,325,735 and 5,732,598 are intended to overcome the deficiencies of the prior art bicycle gear shift indicating devices as described above; nevertheless these two inventions are also not entirely effective in design in that the bicycle speed indicators of various sizes are required for different gear-shifting mechanisms and the indicating range of different speeds, thereby resulting in a substantial increase in cost of making the bicycle gear shift indicators as disclosed in the aforementioned two prior art references.